The present invention relates to a process for producing a fluorine-containing, polymerizable styrene monomer and to intermediates used in the process.
Aromatic polymers produced by polymerization or copolymerization of fluorine-containing styrene monomers are known to be important compounds as resist materials (see Fender. Nicolette et al., Proceedings of SPIE—The International Society for Optical Engineering (2001), vol. 4345, pp. 417-427).
There is known a process for producing a fluorine-containing styrene monomer, 4-(2-hydroxyhexafluoro-2-propyl)styrene, by the steps of (a) reacting 4-ethyl-1-(2-hydroxyhexafluoro-2-propyl)benzene with bromine under light irradiation to produce 1-(1-bromoethyl)-4-(2-hydroxyhexafluoro-2-propyl)benzene, (b) reacting the product of the step (a) with silver acetate to produce 1-(1-acetoxyethyl)-4-(2-hydroxyhexafluoro-2-propyl)benzene, and (c) pyrolyzing the product of the step (b) into the target product of this process, 4-(2-hydroxyhexafluoro-2-propyl)styrene. In this process, silver acetate used in the step (b) is a compound of high price. Furthermore, the pyrolysis of the step (c) may produce the target product with low yield and may be inferior in operation easiness. Thus, this process may be inferior as an industrial production process.
German Patent Application Publication 4207261 discloses a process for producing a fluorine-containing styrene monomer by the steps of (a) reacting 3-bromostyrene with metallic magnesium to produce a Grignard reagent and (b) reacting this Grignard reagent with hexafluoroacetone. This process may be difficult in controlling the reaction. Thus, this process may also be inferior as an industrial production process.